PREPARATION AND CHARACTERIZATION OF [RAC-5,7,7,12,14,14-HEXAMETHYL-1,4,8,11-TETRAAZOCYCLOTETRADECANE]COPPER(II) ORTHO-MERCAPTOBENZOATE HYDRATE, [CU(TET B)(O-SC6H4CO2)].H2O, A COMPLEX WITH A CUN4S (MERCAPTIDE) CHROMOPHORE

The synthesis, crystal structure, electronic spectra, magnetic susceptibility, and ESR data are reported for the title complex. Dark green crystals were obtained in the monoclinic space group P21/n with a = 8.387 (3) Å, b = 21.16 (1) Å, c =14.677 (5) Å, β = 90.92 (3)°, d0bsd = 1.32 (1) g/cm3, dCalcd = 1.322 g/cm3, Z = 4. Least-squares refinement of 1870 reflections having F2 ≥ 2σ gave a conventional R factor of 0.079 and RwF = 0.095. The structure consists of Cu(II) monomers with distorted trigonal bipyramidal N4S ligand donor sets. Structural parameters within the triangular fragment include Cu-S, 2.359 (4) Å Cu-N, 2.193 (10) and 2.132 (9) Å S-Cu-N, 120.8 (3) and 135.4 (3)° and N-Cu-N, 103.5 (4)°. The coordination geometry is completed by two apical Cu-N bonds (2.028 (9), 1.997 (10) Å). Both the X-band ESR spectra (g1 = 2.074, g2 = 2.086 (poorly resolved), g3 = 2.117) and the measured magnetic moment (2.02 (5) μB at 293 K) of the polycrystalline complex support its formulation as a Cu(II) N4S(mercaptide) species. Structural and electronic-spectral data are compared with those reported for analogous CuN4X (X = Cl, CN) species. The title complex exhibits absorptions at ~590 (poorly resolved), 730 (ε ~900), and ~920 nm (shoulder), which are assigned as ligand field transitions. Additional spectral features at 360, 418, and 430 nm which are not exhibited by either free -SC6H4CO2-or a reference Zn(tet b)(o--SC6H4CO2-)•H2O complex are attributed to S → Cu(II) charge transfer. © 1979, American Chemical Society. All rights reserved.